Inertial input apparatus with six-axial detection ability and the operating method thereof

ABSTRACT

An inertial input apparatus with six-axial detection ability, structured with a gyroscope and an acceleration module capable of detecting accelerations of X, Y, Z axes defined by a 3-D Cartesian coordinates, which is operable either being held to move on a planar surface or in a free space. When the inertial input apparatus is being held to move and operate on a planar surface by a user, a two-dimensional detection mode is adopted thereby that the gyroscope is used for detection rotations of the inertial input apparatus caused by unconscious rolling motions of the user and thus compensating the erroneous rotations, by which the technical disadvantages of prior-art inertial input apparatuses equipped with only accelerometer can be overcame and thus control smoothness of using the input apparatus is enhanced.

FIELD OF THE INVENTION

The present invention relates to an inertial input apparatus withsix-axial detection ability and the operating method thereof, and moreparticularly, to an inertial input apparatus configured withaccelerometers and gyroscope, capable of adapting itself to be operativeno matter the inertial input apparatus is being held to operate on aplanar surface or in a free space.

BACKGROUND OF THE INVENTION

There are already several cursor-control devices integrating functionsof the computer mouse and the presentation device. However, the controlmethods adopted thereby are still similar to those conventional computermice and thus suffering the same limitations. As for theinertial/gravity mouse which are being aggressively studied, it is stilltroubled by many technical difficulties and thus remains to be improved.

There are many researches relating to inertial mouse. One of which is aninput device disclosed in U.S. Pat. No. 5,898,421, entitled “GyroscopicPointer and Method”, as seen in FIG. 1. The hand-held input device,having an inertial gyroscope 110 arranged therein, is capable of beingused in free space, employing the inertial gyroscope 110 for detectingangular velocity of a user's hand and thus, by the signal transmissionof the interface 180, defining movements of a cursor displayed on ascreen of an interactive computer. In one embodiment of the aforesaidpatent as that shown in FIG. 1, the inertial gyroscope 110, arrangedinside the hand-held input device, is driven to rotate by power providedfrom a wall adapter 190 and is pivotally coupled to an inner frame 170by a pair of coaxial gimbals 115, 120 while pivotally coupling to anouter frame 160 by another pair of coaxial gimbals 140, 145 whose axisis perpendicular to that of the gimbals 115, 120. As there is only agyroscope 110 configured in the hand-held input device, it is onlysuitable to be used in a free space and is not able to operate on aplanar surface. Moreover, it is conceivable that the referring mouse iscomparably bulky and suffers a high margin of error as gyroscope 110 ismechanically coupled inside the hand-held input device.

Please refer to FIG. 2, which shows a pointing device disclosed in U.S.Pat. No. 5,825,350, entitled “Electronic Pointing Apparatus and Method”.The foregoing pointing apparatus 100 is capable of controlling cursormovement and selecting elements on a computer screen no matter it isbeing held to move on a planar surface or in a free space, in which twogyroscopes, respectively coupled to a gyroscope printed circuit board452, are provided for indicating yaw and pitch movements of the pointingapparatus in free space, and a mouse ball 260 and relating mouse ballencoders are provided for indicating movement of the pointing device ona planar surface. The switching of the pointing apparatus 100 between atwo-dimensional mode and a three-dimensional mode is enabled by a balllocking mechanism, which is comprised of a lever 472 and a plunger 270,connected to the lever 472. That is, when the pointing apparatus 100 isbeing held to move on a planar surface, the plunger 270 that extends outof an opening of the housing is pushed through the opening to a positionsubstantially level with the surface of the bottom side and thus liftsthe lever 472 for freeing the mouse ball 260, so that the pointingapparatus 100 is being enabled to operate in the two-dimensional mode,and when the pointing apparatus 100 is being lift and move in a freespace, the plunger 270 will drop and thus pull the lever 472 to pressdown while enabling the elevated region 506 to press upon the mouse ball260 for holding the same from rolling freely, so that the pointingapparatus 100 is being enabled to operate in the three-dimensional mode.Although the aforesaid pointing apparatus is operable no matter it isbeing held to move on a planar surface or in a free space, it is stillnot preferred, since when the pointing apparatus 100 is being lift andmove in a free space, it is more than likely that the cooperative effortof the lever 472 and its elevated region 506 can not precisely hold themouse ball 260 still that the mouse ball 260 is intended to roll or moveunexpected and causes the pointing apparatus 100 to generate unwantedsignals interfering the cursor movement on the screen.

There are some consumer products, similar to the pointing apparatusshown in FIG. 2, currently available on the market that each can beconsidered as a standard LED optical mouse with addition gyroscopearranged therein and is different from that of FIG. 2 by replacing themouse ball 260 with an optical module and thus the problem caused by theunexpected rolling of the mouse ball is prevented. However, such opticalgyroscope mouse is just a housing accommodating two separated andindependent modules, one acting as a common LED optical mouse whilesitting on a planar surface, and another acting as gyroscope to detectthe angular velocity of rotation while operating in free space, that thecircuit of the LED optical module has no relation with the gyroscopiccircuit. Therefore, not only such optical gyroscope mouse can notbenefit from the design since it can only provide basic functions thesame as the addition of a standard LED optical mouse and a gyroscope,but also it is a heavy, bulky and complicated device.

Please refer to FIG. 3, which is gravity mouse disclosed in TW Pat.Appl. No. 90221010. As the gravity mouse is being held to move and usedfor controlling the movement of a cursor displayed on a monitor of apersonal computer (PC), its gravity sensor (i.e. G sensor) withpotential energy measuring ability is enable to detect the potentialenergy variation of the gravity mouse caused by a movement of the samewhile transmitting a signal generated accordingly to its micro processunit (MCU) to be processed. As the MCU is able to detect the duration ofthe movement while receiving an acceleration caused by the movement, itcan generate a control signal for controlling the cursor to moveaccordingly with respect to the duration and the acceleration. It isknown that the movement of the cursor is determined by a integrationoperation performed based upon the detections of at least twoaccelerometers configuring in the gravity mouse at two perpendicularaxes. Thus, as the movement is defined by integration which is prone toaccumulate error, the positioning of the cursor might not be accurate.

Therefore, it is in need of an inertial sensing input apparatus that isaccurate and convenience to operate no matter it is being held to moveon a surface or in a free space, by which not only the unconsciousrotation caused by a human operation as it is being held in a human handis compensated, but also the interferences caused by the electronicnoises generated from the accelerometer can be prevented for freeing theinertial sensing input apparatus of the invention from the shortcomingsof prior-art inertial input apparatus using only accelerometers.

SUMMARY OF THE INVENTION

In view of the disadvantages of prior art, the primary object of thepresent invention is to provide an inertial input apparatus withsix-axial detection ability, structured with a gyroscope and anacceleration module capable of detecting accelerations of X, Y, Z axesdefined by a 3-D Cartesian coordinates, which is operable either beingheld to move on a planar surface or in a free space. When the inertialinput apparatus is being held to move and operate on a planar surface bya user, a two-dimensional detection mode is adopted thereby that thegyroscope is used for detection rotation of the inertial input apparatuscaused by unconscious rolling motions of the user and thus compensatingthe erroneous rotations, by which the technical disadvantages ofprior-art inertial input apparatuses equipped with only accelerometercan be overcame and thus control smoothness of using the input apparatusis enhanced. In addition, when the inertial input apparatus is beingheld to operate in a free space by a user, a three-dimensional detectionmode is adopted for enabling the inertial input apparatus to detectmovements of the same with respect to at most six axes defined by the3-D Cartesian coordinates of X, Y, Z axes, that is, the rotations withrespect to the X, Y, Z axes and the movements with respect to the X, Y,Z axes, and thus the inertial input apparatus is adapted to be used asan input device for interactive computer games, In a preferred aspect,when the inertial input apparatus is acting as a 3-D mouse suitable tobe used for briefing or in a remote control environment, only thedetections with respect to the X and Y axes acquired by theaccelerometer along with that of the gyroscope are adopts and used ascontrol signals for controlling cursor displayed on a screen, but thedetection with respect to the Z and axis acquired by the accelerometeris used as a switch signal for directing the inertial input apparatus toswitch between its two-dimensional detection mode and three-dimensionaldetection mode.

To achieve the above object, the present invention provides an inertialinput apparatus with six-axial detection ability, comprising:

-   an accelerometer module, structured with at least three    accelerometers for detecting accelerations in three perpendicular    directions with respect to a Cartesian coordinate system of X-, Y-,    and Z-axes; and-   a gyroscope, used for detecting a rotation measured with respect to    the Z-axis;-   wherein, an angle of rotation is obtained by integrating the angular    velocity of the rotation detected by the gyroscope while calculating    a centrifugal force as well as a centripetal force exerting upon the    inertial input apparatus at the moment of the rotation so as to    using those for compensating acceleration signals measured along the    Y-axis and thus obtaining a pitch angle basing on the compensated    Y-axis acceleration signal, thereafter defining movements of an    object displayed on a screen of an interactive computer by the use    of the pitch angle and the angle of rotation.

Preferably, one accelerometer of the acceleration module, referringhereinafter as an X-axis accelerometer, is being enabled for detectingan acceleration generated by a rolling of the inertial input apparatusabout the Y-axis while referring hereinafter such acceleration as X-axisacceleration; another accelerometer of the acceleration module,referring hereinafter as a Y-axis accelerometer, is being enabled fordetecting an acceleration generated by a pitching of the inertial inputapparatus about the X-axis while referring hereinafter such accelerationas Y-axis acceleration; one another accelerometer of the accelerationmodule, referring hereinafter as an Z-axis accelerometer, is beingenabled for detecting an acceleration with respect to the Z-axis whilethe inertial sensing input apparatus is experiencing an up-and-downdisplacement; and the gyroscope is used for detecting and measuring arotation about the Z-axis.

To achieve the above object, the present invention further provide anoperating method for an inertial input apparatus with six-axialdetection ability being held to move in a free space, comprising thesteps of:

-   -   recording two accelerations (g_(xs), g_(ys)) measured along two        perpendicular directions with respect to a Cartesian coordinate        system of X-, and Y-axes at an initial operating stage of the        inertial input apparatus along with an initial angular velocity        ω_(zs) of a gyroscope while setting an initial angle θ_(p) of        the inertial input apparatus to be zero;    -   calculating a yawing angle θ_(z) with respect to a Z-axis of the        Cartesian coordinate system and a pitch angle θ_(y) with respect        to the Y-axis; and    -   using the two angles (θ_(z), θ_(y)) to define a position        coordinate (M_(x), M_(y)) for an object displayed on a screen of        an interactive computer.

Preferably, the calculating of the yawing angle θ_(z) and the pitchangle θ_(y) further comprises the steps of:

-   -   calculating the yawing angle θ_(z) with respect to the Z-axis by        the following formulas:        θ_(z)=θ_(p)+(ω_(z)-ω_(zs))×Δt, while |ω_(z)-ω_(zs)| is larger        than a threshold value,    -   wherein Δt is the sampling interval, preferably every 10        mini-sec,        -   the threshold value is preferably being set to be 0.1            (degree/sec) so as to eliminate noise correspondingly,    -   and then let θ_(p)=θ_(z);    -   compensating a Y-axis acceleration detected by a Y-axis        accelerometer of an acceleration module by subtracting a        centripetal force g_(r) from an actual acceleration g_(a)        detected by the Y-axis accelerometer, as illustrated in the        following formulas:        g _(a) =g _(r) +g _(s);        g _(r) =R×(ω_(z) −ω _(zs))²;        g _(y) =g _(a) −g _(r);    -   wherein R is the distance between a rotation center and the        accelerometer;        -   g_(s) is acceleration caused by other electrical noises;        -   g_(y) is the compensated Y-axis acceleration;    -   calculating the pitch angle θ_(y) with respect to the Y-axis        using the compensated Y-axis acceleration g_(y) by the following        formulas:

$\theta_{y} = {\sin^{- 1}\left( \frac{g_{y} - g_{ys}}{g_{ys}} \right)}$

Preferably, the two angles (θ_(z), θ_(y)) are amplified by specificratios in respective so as to be used for defining a position coordinate(M_(x), M_(y)) for an object displayed on a screen of an interactivecomputer, according to the following formulas:M _(s) =S _(x)×θ_(z) , M _(y) =S _(y)×θ_(y);

-   -   wherein S_(x) is the amplifying ratio with respect to the        X-axis;        -   S_(y) is the amplifying ratio with respect to the Y-axis.

Preferably, the method further comprises a page-change detection step,which use an abrupt change in X-axis acceleration detected by theinertial input apparatus as a page-change signal by comparing the abruptchange with a threshold value. In a preferred aspect, by defining athreshold value thr as 150 count, the page-change detection step isstructured as following:

-   -   paging up if (g_(x)−g_(xz))>thr; and paging down if        (g_(x)−g_(xz))<−thr; or vice versa    -   maintaining without page change if −thr≦(g_(x)−g_(xz))≦thr;    -   wherein g_(x) is an X-axis acceleration at the end of an abrupt        change occur;        -   g_(xs) is an X-axis acceleration at the beginning of an            abrupt change occur.            It is noted that the threshold value thr can be adjusted at            will with respect to any actual requirement.

In another preferred embodiment, the method further comprises anotherpage-change detection step, which uses a rolling angle θ_(x) withrespect to the X-axis as a page-change signal by comparing the rollingangle θ_(x) with a threshold value. In a preferred aspect, by definingthe threshold value thr as 30 degree, the page-change detection step isstructured as following:

paging up if θ_(x)>thr; and paging down if θ_(x)<−thr; or vice versa;

-   -   maintaining without page change if −thr≦θ_(x)≦thr.

In addition, the present invention further provide a method forswitching an inertial input apparatus with six-axial detection abilitybetween a two-dimensional detection mode and a three-dimensionaldetection mode, comprising the steps of:

-   -   recording three initial accelerations (g_(xz), g_(yz), g_(zs))        measured along three perpendicular directions with respect to a        Cartesian coordinate system of X-, Y- and Z-axes respectively by        an acceleration module of the inertial input apparatus while the        inertial input apparatus is at rest on a surface along with an        initial angular velocity ω_(zs) of a gyroscope and setting an        initial angle θ_(p) of the inertial input apparatus to be zero        and enabling the inertial input apparatus to enter the        two-dimensional detection mode;    -   double-integrating the difference between the initial        acceleration g_(zs) and current accelerations detected by a        Z-axis accelerometer of the acceleration module for obtaining a        mode-change value S_(Z), i.e. S_(Z)=∫∫(g_(z)−g_(zs));    -   comparing S_(Z) with a threshold value thr;    -   maintaining the inertial input apparatus at the two-dimensional        detection mode when S_(Z)<thr; and    -   enabling the inertial input apparatus to enter the        three-dimensional detection mode when S_(Z)>thr.

Preferably, the inertial input apparatus is enabled to enter thethree-dimensional detection mode when a plurality of mode-change valuesS_(Z) detected within a specific time interval are all larger than thethreshold value thr.

Preferably, the inertial input apparatus is enabled to enter thetwo-dimensional detection mode when the mode-change values S_(Z) issmaller than the threshold value thr and the absolute differencesbetween the inertial acceleration g_(ys) and a plurality of Y-axisaccelerations g_(y) detected by a Y-axis accelerometer of theacceleration module within a specific time interval, i.e.|g_(y)−g_(yz)|, are all smaller than a specific value or almost equal tozero.

Other aspects and advantages of the present invention will becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawings, illustrating by way of example theprinciples of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an expanded perspective view of an input device, disclosed inU.S. Pat. No. 5,898,421, entitled “Gyroscopic Pointer and Method”.

FIG. 2 shows a pointing device disclosed in U.S. Pat. No. 5,825,350,entitled “Electronic Pointing Apparatus and Method”.

FIG. 3 is gravity mouse disclosed in TW Pat. Appl. No. 90221010.

FIG. 4 shows an inertial sensing input apparatus of the invention, beingdefined in three perpendicular directions with respect to a Cartesiancoordinate system of X-, Y-, and Z-axes.

FIG. 5 is a flow chart depicting an operating method for an inertialinput apparatus with six-axial detection ability being held to move in afree space.

FIG. 6 is a flow chart depicting steps for calculating a yawing angleθ_(z) with respect to a Z-axis of the Cartesian coordinate system and apitch angle θ_(y) with respect to the Y-axis.

FIG. 7 is a flow chart depicting steps for page-change detection.

FIG. 8 is a schematic diagram showing forces exerting on a Y-axisaccelerometer of the inertial input apparatus while the inertial inputapparatus is rotating.

FIG. 9 is a flow chart depicting steps of switching an inertial inputapparatus between a two-dimensional detection mode and athree-dimensional detection mode.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For your esteemed members of reviewing committee to further understandand recognize the fulfilled functions and structural characteristics ofthe invention, several preferable embodiments cooperating with detaileddescription are presented as the follows.

Please refer to FIG. 4, which shows an inertial sensing input apparatusof the invention, being defined in three perpendicular directions withrespect to a Cartesian coordinate system of X-, Y-, and Z-axes. Theinertial sensing input apparatus with six-axial detection ability 10 iscomprised of: an accelerometer module 11, structured with at least threeaccelerometers for detecting accelerations in three perpendiculardirections with respect to a Cartesian coordinate system of X-, Y-, andZ-axes; and a gyroscope 12, used for detecting a rotation measured withrespect to the Z-axis; wherein, one accelerometer of the accelerationmodule 11, referring hereinafter as an Z-axis accelerometer 113, isbeing enabled for detecting an acceleration with respect to the Z-axiswhile the inertial input apparatus 10 is experiencing an up-and-downdisplacement and thus determining whether to enable the same to enter atwo-dimension (2D) detection mode or a three-dimension (3D) detectionmode. Moreover, when the inertial input apparatus 10 is operating underthe three-dimension (3D) detection mode, one accelerometer of theacceleration module, referring hereinafter as an X-axis accelerometer111, is being enabled for detecting an acceleration generated by arolling of the inertial input apparatus about the Y-axis to be used forcalculating a rolling angle θ_(x); another accelerometer of theacceleration module, referring hereinafter as a Y-axis accelerometer112, is being enabled for detecting an acceleration generated by apitching of the inertial input apparatus about the X-axis to be used forcalculating a pitching angle θ_(y); and an yawing angle θ_(z) isobtained by the processing of angular velocity signals detected by thegyroscope 12. In addition, the X-axis accelerometer 111, the Y-axisaccelerometer 112, and the Z-axis accelerometer 113 are capable ofdetecting and measuring accelerations along the X-axis, the Y-axis andthe Z-axis in respective for defining the movements of the inertialinput apparatus 10 in the directions of X-, Y-, and Z-axes inrespective.

With the aforesaid inertial input apparatus with six-axial detectionability 10, an operating method for the inertial input apparatus 10 asit is being held to move in a free space can be provided. Please referto FIG. 5 and FIG. 6, which illustrate an operating method for aninertial input apparatus with six-axial detection ability being held tomove in a free space. The operating method 50 of FIG. 5 comprises thesteps of:

-   Step 51: recording two accelerations (g_(xs), g_(ys)) measured along    two perpendicular directions with respect to a Cartesian coordinate    system of X-, and Y-axes at an initial operating stage of the    inertial input apparatus along with an initial angular velocity    ω_(zs) of a gyroscope while setting an initial angle θ_(p) of the    inertial input apparatus to be zero;-   Step 52: calculating a yawing angle θ_(z) with respect to a Z-axis    of the Cartesian coordinate system and a pitch angle θ_(y) with    respect to the Y-axis; in a preferred aspect, as seen in FIG. 6, the    step 52 further comprises the following steps:    -   Step 521: calculating the yawing angle θ_(z) with respect to the        Z-axis by the following formulas:        θ_(z)=θ_(p)+(ω_(z)−ω_(zs))×Δt  (1)        -   while |ω_(z)−ω_(zs)| is larger than a threshold value,        -   wherein Δt is the sampling interval, preferably every 10            mini-sec,        -   the threshold value is preferably being set to be 0.1 so as            to eliminate noise correspondingly,        -   and then let θ_(p)=θ_(z);    -   Step 522: compensating a Y-axis acceleration detected by a        Y-axis accelerometer of an acceleration module by subtracting a        centripetal force g_(r) from an actual acceleration g_(a)        detected by the Y-axis accelerometer, as illustrated in the        following formulas:        g _(r) =R×(ω_(z)−ω_(zs))²;  (2-1)        g _(a) =g _(r) +g _(s);  (2-2)        g _(y) =g _(a) −g _(r);  (3)        -   wherein R is the distance between a rotation center and the            accelerometer; as seen In FIG. 8 where Hc represent a center            of rotation;            -   g_(s) is acceleration caused by other electrical noises;            -   g_(y) is the compensated Y-axis acceleration;        -   the compensation is based on a concept that when the            inertial input apparatus 10 is rotating, the Y-axis            accelerometer will be subjected to an additional centripetal            force which can be measured by the use of the angular            velocity detected by the gyroscope 12 and it radius of            rotation. Thus, by subtracting a centripetal force g_(r)            from an actual acceleration g_(a) detected by the Y-axis            accelerometer, as seen in (2-2), an compensated Y-axis            acceleration g_(y) is obtained;    -   Step 523: calculating the pitch angle θ_(y) with respect to the        Y-axis using the compensated Y-axis acceleration g_(y) by the        following formulas:

$\begin{matrix}{\theta_{y} = {\sin^{- 1}\left( \frac{g_{y} - g_{ys}}{g_{ys}} \right)}} & (4)\end{matrix}$

-   -    It is noted that, by the detection of the gyroscope 12, an        unconscious rotation of inertial input apparatus 10 as it is        being held to move thereby can be compensated so that not only        the inertial sensing input apparatus of the invention is freed        from the shortcomings of prior-art inertial input apparatus        using only accelerometer, but also it is a device that can be        handle smoothly and naturally.

-   Step 53: using the two angles (θ_(z), θ_(y)) to define a position    coordinate (M_(x), M_(y)) for an object displayed on a screen of an    interactive computer; in which the two angles (θ_(z), θ_(y)),    obtained in step 521 and step 523, are amplified by specific ratios    in respective so as to be used for defining a position coordinate    (M_(x), M_(y)) for an object displayed on a screen of an interactive    computer, according to the following formulas:    M _(s) =S _(x)×θ_(z) , M _(y) =S _(y)×θ_(y);  (5)    -   wherein S_(x) is the amplifying ratio with respect to the        X-axis;        -   S_(y) is the amplifying ratio with respect to the Y-axis;    -   It is noted that the specific ratios S_(, S) _(y) are        adjustable.

-   Step 54: performing a page-change detection, which use an abrupt    change in X-axis acceleration detected by the inertial input    apparatus as a page-change signal by comparing the abrupt change    with a threshold value, as seen in FIG. 7, further comprising the    steps of:    -   Step 541: defining a threshold value thr; whereas the threshold        value thr is adjustable with respect to actual requirement, e.g.        defining thr=150 (count);    -   Step 542: comparing (g_(x)−g_(xs)) with thr so as to use the        comparison to determine whether to perform a page-up operation        or a page-down operation, whereas g_(x) is an X-axis        acceleration at the end of an abrupt change occur, and g_(xs) is        an X-axis acceleration at the beginning of an abrupt change        occur;    -   Step 543: paging up if (g_(x)−g_(xs))>thr;    -   Step 544: paging down if (g_(x)−g_(xs))<−thr;        -   It is noted that the condition of the aforesaid paging up            and down can be reversed, as that paging down if            (g_(x)−g_(xs))>thr; and paging up if (g_(x)−g_(xs))<−thr;            moreover, if −thr≦(g_(x)−g_(xs))≦thr, it is specified as an            unconscious movement of a user and thus no page change will            be performed.

In addition to the aforesaid page changing using abrupt accelerationchange as page-change signal, a rolling angle θ_(x) with respect theY-axis can be used as a page-change signal by comparing the rollingangle θ_(x) with a threshold value. Similarly, first, a threshold valuethr is defined, e.g. defining thr=30°; and then the page-changedetection step is structured as following:

paging up if θ_(x)>thr; and paging down if θ_(x)<−thr; or vice versa;

maintaining without page change if −thr≦θ_(x)≦thr.

Moreover, referring to FIG. 9, the present invention further provide amethod for switching an inertial input apparatus with six-axialdetection ability between a two-dimensional detection mode and athree-dimensional detection mode, comprising the steps of:

-   Step 81: recording three initial accelerations (g_(xs), g_(ys),    g_(zs)) measured along three perpendicular directions with respect    to a Cartesian coordinate system of X-, Y- and Z-axes respectively    by an acceleration module of the inertial input apparatus while the    inertial input apparatus is at rest on a surface along with an    initial angular velocity ω_(zs) of a gyroscope and setting an    initial angle θ_(p) of the inertial input apparatus to be zero and    enabling the inertial input apparatus to enter the two-dimensional    detection mode;-   Step 82: double-integrating the difference between the initial    acceleration g_(zs) and current accelerations detected by a Z-axis    accelerometer of the acceleration module for obtaining a mode-change    value S_(Z), i.e. S_(Z)=∫∫(g_(z)−g_(zs));-   Step 83: comparing S_(Z) with a threshold value thr;-   Step 84: maintaining the inertial input apparatus at the    two-dimensional detection mode when S_(Z)<thr; and-   Step 85: enabling the inertial input apparatus to enter the    three-dimensional detection mode when S_(Z)>thr, which indicates the    inertial input apparatus has be lifted from the surface to be used    as a pointing device, such as a presentation device, and thus the    inertial input apparatus is enabled to enter its three-dimension    detection mode for performing tasks, such as page changing as    indicated in FIG. 5˜FIG. 7; and-   Step 86: enabling the inertial input apparatus to enter the    two-dimensional detection mode when the mode-change values S_(Z) is    smaller than the threshold value thr and the absolute differences    between the inertial acceleration g_(ys) and a plurality of Y-axis    accelerations g_(y) detected by a Y-axis accelerometer of the    acceleration module within a specific time interval, i.e.    |g_(y)−g_(ys), are all smaller than a specific value or almost equal    to zero.

For further freeing the inertial input apparatus from errors caused byunconscious movements of a user holding the same, the inertial inputapparatus can be set to enter the three-dimensional detection mode onlywhen a plurality of mode-change values S_(Z) detected within a specifictime interval are all larger than the threshold value thr. Similarly,the inertial input apparatus is enabled to enter the two-dimensionaldetection mode when the mode-change values S_(Z) is smaller than thethreshold value thr and the absolute differences between the inertialacceleration g_(ys) and a plurality of Y-axis accelerations g_(y)detected by a Y-axis accelerometer of the acceleration module within aspecific time interval, i.e. |g_(y)−g_(ys)|, are all smaller than aspecific value or almost equal to zero.

To sum up, the present invention relates to an inertial input apparatuswith six-axial detection ability, structured with a gyroscope and anacceleration module capable of detecting accelerations of X, Y, Z axesdefined by a 3-D Cartesian coordinates, which is operable either beingheld to move on a planar surface or in a free space. When the inertialinput apparatus is being held to move and operate on a planar surface bya user, a two-dimensional detection mode is adopted thereby that thegyroscope is used for detection rotations of the inertial inputapparatus caused by unconscious rolling motions of the user and thuscompensating the erroneous rotations, by which the technicaldisadvantages of prior-art inertial input apparatuses equipped with onlyaccelerometer can be overcame and thus control smoothness of using theinput apparatus is enhanced. In addition, when the inertial inputapparatus is being held to move and operate in a free space by a user, athree-dimensional detection mode is adopted for enabling the inertialinput apparatus to detect movements of the same with respect to at mostsix axes defined by the 3-D Cartesian coordinates of X, Y, Z axes, thatis, the rotations with respect to the X, Y, Z axes and the movementswith respect to the X, Y, Z axes, and thus the inertial input apparatusis adapted to be used as an input device for interactive computer games,In a preferred aspect, when the inertial input apparatus is acting as a3-D mouse suitable to be used for briefing or in a remote controlenvironment, only the detections with respect to the X and Y axesacquired by the accelerometer along with that of the gyroscope areadopts and used as control signals for controlling cursor displayed on ascreen, but the detection with respect to the Z-axis acquired by theaccelerometer is used as a switch signal for directing the inertialinput apparatus to switch between its two-dimensional detection mode andthree-dimensional detection mode.

While the preferred embodiment of the invention has been set forth forthe purpose of disclosure, modifications of the disclosed embodiment ofthe invention as well as other embodiments thereof may occur to thoseskilled in the art. Accordingly, the appended claims are intended tocover all embodiments which do not depart from the spirit and scope ofthe invention.

1. A method for switching an inertial input apparatus with six-axialdetection ability between a two-dimensional detection mode and athree-dimensional detection mode, comprising the steps of: recordingthree initial accelerations (g_(xs), g_(ys),g_(zs)) measured along threeperpendicular directions with respect to a Cartesian coordinate systemof X-, Y- and Z-axes respectively by an acceleration module of theinertial input apparatus while the inertial input apparatus is at reston a planar surface along with an initial angular velocity ω_(zs)gyroscope and setting an initial angle θ_(p) of the inertial inputapparatus to be zero and enabling the inertial input apparatus to enterthe two-dimensional detection mode; double-integrating the differencebetween the initial acceleration g_(zs) and current accelerationsdetected by a Z-axis accelerometer of the acceleration module forobtaining a mode-change value S_(z), i.e. S_(z)=∫∫(g_(z)−g_(zs));comparing S_(z) with a threshold value thr; maintaining the inertialinput apparatus at the two-dimensional detection mode when S_(z)<thr;and enabling the inertial input apparatus to enter the three-dimensionaldetection mode when S_(z)>thr.
 2. The method of claim 1, wherein theinertial input apparatus is enabled to enter the three-dimensionaldetection mode when a plurality of mode-change values S_(z) detectedwithin a specific time interval are all larger than the threshold valuethr.
 3. The method of claim 1, wherein the inertial input apparatus isenabled to enter the two-dimensional detection mode when the mode-changevalues S_(z) is smaller than the threshold value thr and the absolutedifferences between the inertial acceleration g_(ys) and a plurality ofY-axis accelerations g_(Y) detected by a Y axis accelerometer of theacceleration module within a specific time interval, i.e.|g_(y)−g_(ys)|, are all smaller than a specific value or almost equal tozero.
 4. An operating method for an inertial input apparatus withsix-axial detection ability being held to move in a free space,comprising the steps of: recording two accelerations (g_(xs), g_(ys))measured along two perpendicular directions with respect to a Cartesiancoordinate system of X-, and Y-axes at an initial operating stage of theinertial input apparatus along with an initial angular velocity ω_(zs)of a gyroscope while setting an initial angle θ_(p) of the inertialinput apparatus to be zero; calculating a yawing angle θ_(z) withrespect to a Z-axis of the Cartesian coordinate system and a pitch angleθ_(y) with respect to the Y-axis, further comprises the steps of:calculating the yawing angle θ_(z) with respect to the Z-axis;compensating a Y-axis acceleration detected by a Y-axis accelerometer ofan acceleration module; and calculating the pitch angle θ_(y); and usingtwo angles (θ_(z), θ_(y)) to define a position coordinate (M_(x), M_(y))for an object displayed on a screen of an interactive computer; anddetecting a page-change, comprising the steps of: defining a thresholdvalue thr; calculating a rolling angle θ_(x) with respect the Y-axis;and comparing the rolling angle θ_(x) with thr so as to use thecomparison to determine whether to perform a page-up operation or apage-down operation.
 5. The method of claim 4, wherein the step ofcalculating the yawing angle θ_(z) with respect to the Z-axis isperformed by the following formulas:θ_(z)=θ_(p)+(ω_(z)−ω_(zs))×Δt, while |ω_(z)−ω_(zs)| is larger than athreshold value, wherein Δt is the sampling interval, preferably every10 mini-sec, the threshold value is preferably being set to be 0.1 so asto eliminate noise correspondingly, and then let θ_(p)=θ_(z).
 6. Themethod of claim 4, wherein the step of compensating a Y-axisacceleration detected by a Y-axis accelerometer of an accelerationmodule is perform by subtracting a centripetal force g_(r) from anactual acceleration g_(a) detected by the Y-axis accelerometer, asillustrated in the following formulas:g _(a=) g _(r+) g _(s);g _(r)=R×(ω_(z−ω) _(zs))²;g _(y=) g _(a−) g _(r); wherein R is the distance between a rotationcenter and the accelerometer; g_(s) is acceleration caused by otherelectrical noises; g_(y) is the compensated Y-axis acceleration.
 7. Themethod of claim 4, wherein the step of calculating the pitch angle θ_(y)with respect to the Y-axis using the compensated Y-axis accelerationg_(y) is performed by the following formulas:$\theta_{y} = {{\sin^{- 1}\left( \frac{g_{y} - g_{ys}}{g_{ys}} \right)}.}$8. An operating method for an inertial input apparatus with six-axialdetection ability being held to move in a free space, comprising thesteps of: recording two accelerations (g_(xs), g_(ys)) measured alongtwo perpendicular directions with respect to a Cartesian coordinatesystem of X-, and Y-axes at an initial operating stage of the inertialinput apparatus along with an initial angular velocity ω_(zs) of agyroscope while setting an initial angle θ_(p) of the inertial inputapparatus to be zero; calculating a yawing angle θ_(z) with respect to aZ-axis of the Cartesian coordinate system and a pitch angle θ_(y) withrespect to the Y-axis; and using two angles (θ_(z), θ_(y)) to define aposition coordinate (M_(x), M_(y)) for an object displayed on a screenof an interactive computer; wherein the two angles (θ_(z), θ_(y)) areamplified by specific ratios S_(x), S_(y) in respective so as to be usedfor defining a position coordinate (M_(x), M_(y)) for an objectdisplayed on a screen of an interactive computer, according to thefollowing formulas:M _(s)=S _(x)×θ_(z), M _(y)=S _(y)×θ_(y) wherein S_(x) is the amplifyingratio with respect to the X-axis, and S_(y) is the amplifying ratio withrespect to the Y-axis.
 9. The method of claim 8, wherein the specificratios S_(x), S_(y) are adjustable.
 10. The method of claim 4, detectingthe page-change, further comprising the steps of: comparing(g_(x)−g_(xs)) with thr so as to use the comparison to determine whetherto perform a page-up operation or a page-down operation, whereas g_(x)is an X-axis acceleration at the end of an abrupt change occur, andg_(xs) is an X-axis acceleration at the beginning of an abrupt changeoccur.
 11. The method of claim 10, wherein the page-change detectionstep further comprises the steps of: paging up if (g_(x)−g_(xs))>thr;and paging down if (g_(x)−g_(xs))<−thr.
 12. The method of claim 11,further comprising the step of: maintaining without page change if−thr≦(g_(x)−g_(xs))≦thr.
 13. The method of claim 10, wherein thepage-change detection step further comprises the steps of: paging downif (g_(x)−g_(xs))>thr; and paging up if (g_(x−g) _(xs))<−thr.
 14. Themethod of claim 13, wherein further comprising the step of: maintainingwithout page change if −thr≦(g_(x)−g_(xs))≦thr.
 15. The method of claim10, wherein the threshold value thr is adjustable according to actualrequirement.
 16. The method of claim 4, wherein the page-changedetection step further comprises the steps of: paging down if θhd x>thr;and paging up if θ_(x)<−thr.
 17. The method of claim 16, wherein furthercomprising the step of: maintaining without page change if−thr≦θ_(x)≦thr.
 18. The method of claim 4, wherein the page-changedetection step further comprises the steps of: paging up if θ_(x)>thr;and paging down if θ_(x)<−thr.
 19. The method of claim 18, whereinfurther comprising the step of: maintaining without page change if−thr≦θhd x≦thr.